import bitOperation.lee461_hammingDistance;

import java.io.*;

/**
 * @author gh
 * @create 2021-05-27 7:14
 */
public class demo {

    //out
    public static void main(String[] args) throws IOException {

        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        String line;
        while ((line = in.readLine()) != null) {
            int x = Integer.parseInt(line);
            line = in.readLine();
            int y = Integer.parseInt(line);

            int ret = new lee461_hammingDistance().hammingDistance(x, y);

            System.out.print(String.valueOf(ret));
        }
    }
}
